United Airlines planes sit on the tarmac at San Francisco International Airport on July 8, grounded by a computer glitch. Some 3,500 United passengers around the world were delayed.
Justin Sullivan/Getty Images
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A United Airlines 747-400 taxis at San Francisco International Airport in 2011. A group of flight attendants have filed suit against the airline to contest their firing over their handling of a perceived safety threat.
Eric Risberg/AP
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